WO2012011682A2

WO2012011682A2 - Device and method for measuring skin structure

Info

Publication number: WO2012011682A2
Application number: PCT/KR2011/004883
Authority: WO
Inventors: 한지연; 남개원; 김명준
Original assignee: (주)아모레퍼시픽
Priority date: 2010-07-22
Filing date: 2011-07-04
Publication date: 2012-01-26
Also published as: JP2013538070A; WO2012011682A3; JP5921543B2

Abstract

The invention relates to a device for measuring skin structure, which may include: a plurality of light sources arranged in respectively different directions with respect to the portion of skin to be measured, and configured to sequentially emit light on the skin; and a unit for capturing an image of the skin and generating a plurality of images corresponding to each of the plurality of light sources. The method for measuring skin structure may include the steps of: sequentially emitting light in a plurality of mutually different light-emitting directions and capturing a plurality of images corresponding to each of the plurality of light-emitting directions; and using the plurality of brightness levels of the plurality of images to generate a normal map corresponding to the information on the normal to the surface of the skin.

Description

【Specification】

[Name of invention]

Skin structure measuring device and method

Technical Field

Embodiments relate to an apparatus and method for measuring skin structure.

Background Art

<2> Techniques for measuring microstructures, such as wrinkles or pores in the skin, or for recreating them into images on a computer, have been considered important functions in various imaging systems. In particular, with the development of mobile devices equipped with charge coupled devices (CCDs), cosmetic diagnosis systems, and telemedicine, technology for accurately measuring the microstructure of skin is suitable for visual communication and skin cosmetics. Increasingly, the use of medical choices or medical diagnosis is increasing.

[Detailed Description of the Invention]

[Technical problem]

According to an aspect of the present invention, by taking a picture of the subject's skin while changing the position of the light source, it is possible to obtain information about the fine structure, such as wrinkles or pores on the skin using the photographed image It is possible to provide an apparatus and method for measuring skin structure that can represent this as an image.

Technical Solution

According to one or more exemplary embodiments, an apparatus for measuring skin structure may include: a plurality of light sources arranged in different directions with respect to a skin to be measured and configured to sequentially irradiate light onto the skin; And a photographing unit which photographs the skin to generate a plurality of images respectively reflected by the plurality of light sources.

The skin structure measuring apparatus may further include a fixing unit configured to fix the position of the skin.

The skin structure measuring apparatus may further include a support part configured to support the photographing part and the plurality of light sources and to be movable with respect to the skin.

The apparatus for measuring skin structure may further include an analyzer configured to calculate structure information of the skin using the plurality of images.

The analysis unit may include a normal calculation unit configured to generate a 1 normal map that is subjected to normal information of the skin by using brightnesses of the plurality of images.

<9> The analysis unit, based on the microstructure information of the skin using the first normal map The apparatus may further include a microstructure calculator configured to generate a second normal map.

The analysis unit may further include a wrinkle component calculation unit configured to generate a scalar map that is subjected to wrinkle component information of the skin using the crab normal map.

The analysis unit may further include an elasticity calculator that calculates skin elasticity information from the first normal map.

According to one or more exemplary embodiments, a method for measuring skin structure may include: photographing a plurality of images supported in each of the plurality of light irradiation directions while sequentially irradiating light to the skin in a plurality of different light irradiation directions; And generating a first normal map that is subjected to normal information on the surface of the skin by using brightnesses of the plurality of images.

The skin structure measuring method may further include generating a low frequency map corresponding to skin contour information by applying a Gaussian filter to the first normal map; And generating a second normal map that is subtracted from the microstructure information of the skin by removing the low frequency map from the first normal map.

The skin structure measuring method may include: generating a two-dimensional vector map by extracting a horizontal component from the second normal map; And generating a scalar map corresponding to the wrinkle component information of the skin by applying an elliptical Gaussian filter to the two-dimensional vector map.

The skin structure measuring method may further include calculating skin elasticity information from the first normal item.

Advantageous Effects

When using the apparatus and method for measuring skin structure according to an aspect of the present invention, a normal map corresponding to a microstructure such as wrinkles or pores present in the skin is obtained from the skin image photographed while changing the position of the light source. The generated normal map can be displayed as an image. Through the generated image, it is possible to visually check the improvement of skin structure before and after using a specific cosmetic product. [Brief Description of Drawings]

La to H are views illustrating a skin structure measuring apparatus according to an embodiment.

2A and 2B are views showing a fixture that may be used to fix the subject's position.

3A to 3C illustrate the blood of a subject by using a skin structure measuring apparatus according to an embodiment. It is a photograph showing an image of a part.

4 is a block diagram illustrating an analyzer in a skin structure measuring apparatus according to an exemplary embodiment.

FIG. 5 is a schematic diagram illustrating a process of generating a first normal map in a skin structure measuring apparatus according to an exemplary embodiment.

6A and 6B are images representing a normal map generated by a skin structure measuring apparatus according to an exemplary embodiment.

FIG. 7 is an image displayed on a low frequency map calculated from a first normal map according to a skin structure measuring apparatus according to an exemplary embodiment.

8A and 8B illustrate an image reflected on a second normal map generated from a first normal map according to an apparatus for measuring skin structure, according to an exemplary embodiment.

FIG. 9 is an image displayed on a scalar map generated from a second normal map according to an apparatus for measuring skin structure according to an exemplary embodiment.

10 is a flowchart illustrating a method for measuring skin structure according to an embodiment.

[Form for implementation of invention]

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

La to If are views illustrating a skin structure measuring apparatus according to an embodiment. La is a perspective view of the device, and lb and lc are left and right side views of the device, respectively. Figure ID is a top view of the device, and Figures le and If are front and back views of the device, respectively.

Referring to FIGS. La to If, the apparatus for measuring skin structure according to an embodiment may include a plurality of light sources 10 and a photographing unit 20. In addition, in one embodiment, the skin structure measuring apparatus may further include a support part 40 for supporting the light source 10 and the photographing part 20.

The plurality of light sources 10 are devices for irradiating light onto the skin of a subject. In one embodiment, each light source 10 may be a flash device mainly used for cameras and the like. In one embodiment, the light source 10 may be a metal halide lamp. Metal halide lamps have a color close to sunlight, and can have an effect close to a point light source because of their small size. By using the metal halide lamp as the light source 10, the skin image can be easily taken in a general environment, not in the dark room. Therefore, by using the skin structure measuring device in the retailer of cosmetic products, by taking images of the skin of the consumer and measuring the skin structure, it is possible to confirm the efficacy of the product, etc. There is an advantage to that.

However, this is exemplary and the light source 10 may be a light emitting diode or other different light irradiation means in addition to the metal halide lamp. In addition, a reflector (not shown) and / or a polarizing filter (not shown) may be used together with the light source 10.

The plurality of light sources 10 may be arranged to irradiate the skin with light from different directions. In addition, the plurality of light sources 10 may be arranged symmetrically or asymmetrically about the subject. For example, in FIGS. La to If, twelve light sources 10 are arranged in a hemispherical shape centered on the subject's position. However, as an example, the plurality of light sources 10 do not necessarily have to be arranged in a hemispherical shape, and may be arranged in a spherical shape completely surrounding the subject or in other different arrangements. In addition, the number of the light sources 10, the distance between the light sources 10, and the distance between the light sources 10 and the subject may also be different from those shown in the drawings.

The photographing unit 20 may be configured to photograph the subject's skin image in a state where the light is irradiated by the plurality of light sources 10 positioned in front of the subject. In this case, the plurality of light sources 10 may sequentially irradiate light, and the photographing unit 20 may be synchronized with each light source 10 to capture an image in a state where light is irradiated by each light source 10. Can be configured. As a result, a plurality of images are generated in the photographing unit 20, and each image represents skin in which light is irradiated by a different light source 10. That is, a plurality of skin images having different light irradiation directions can be obtained.

In one embodiment, the light source 10 and the imaging unit 20 may be fixed to the movable support 40. For example, the support 40 may be a structure on which the wheel is attached, and the position of the light source 10 and the photographing unit 20 for the subject may be changed by moving the support 40 using the wheel.

Meanwhile, in order to measure the skin structure, a plurality of images photographing the same position are required. Therefore, in one embodiment, the skin structure measuring apparatus may further include a separate fixing unit for fixing the position of the subject. FIG. 2A is a perspective view showing the fixing part 30, and FIG. 2B is a front view of the fixing part 30 of FIG. 2A.

Referring to FIGS. 2A and 2B, the body part of the subject (eg, the head of the subject) to be photographed using the fixing part 30 may be fixed. For example, the subject may photograph the subject's face skin while his / her jaw is covered by the fixed part 30. However, the shape of the fixing part 30 shown in FIGS. 2A and 2B is merely exemplary. In addition, the fixation part 30 may be configured by other different means for fixing the subject's position. Alternatively, the skin image of the subject may be photographed without using a separate fixing part.

Using the skin structure measuring apparatus described above, a plurality of images obtained by measuring skin while irradiating light from different light irradiation directions can be obtained. Degree

3A to 3C are photographs showing images of the skin measured by the skin structure measuring apparatus shown in FIG. 1, and FIGS. 3A to 3C are skin images measured while irradiating light to the skin from different light irradiation directions, respectively.

In one embodiment, the skin structure measuring apparatus may further include an analysis unit for calculating the structure information of the skin by using the plurality of images. In this specification, an analysis unit may refer to a computer-related entity such as hardware, a combination of hardware and software, or software. For example, the analysis unit 50 may include a running process, a processor, an object, an executable, a thread of execution, a program, and / or a computer, but are not limited thereto. no. For example, both an application running on a computer and a computer may correspond to the analysis unit.

4 is a block diagram illustrating an analysis unit included in a skin structure measuring apparatus, according to an exemplary embodiment.

Referring to FIG. 4, the analyzer 50 may include a normal calculator 51, a microstructure calculator 52, and a wrinkle component calculator 53. The normal calculation unit 51 includes a first normal map including normal information on the surface of the skin by using a plurality of images having different light irradiation directions.

You can create a normal map. In the present specification, the normal map refers to skin structure information obtained by calculating normal information of a skin surface of an area corresponding to each pixel using brightness information of each pixel in an image of a skin surface. All. Such a normal map may be displayed in the form of an image having a color and / or a shade that is reflected in the normal information at each pixel.

Hereinafter, a process of generating a first normal map that is subjected to normal information on the surface of the skin by using the plurality of images in the normal calculation unit 51 will be described in detail.

FIG. 5 is a schematic diagram for explaining a process of generating a first normal map. FIG. Referring to FIG. 5, the intensity of light irradiated from the light source 10 and reflected from the surface of the skin 1 may be expressed by Equation 1 using a Phong reflection model. <43> [Equation 1]

_<44> I = K _D (N. L) I _L + K _S {V.RY I _L

In Equation 1, I _L represents the intensity of incident light from the light source 10, and I represents the intensity of light reflected from the surface of the skin 1. K _D represents the diffuse reflection constant of skin (1), ¾ is the specular reflection constant of skin (1)

(specular reflection constant). N is a vector representing the normal of the surface of the skin 1, and V is a vector representing the direction of observation, and is plotted on the direction of the imaging section 20 relative to the skin 1. In addition, L is a vector which shows the direction of incident light with respect to the skin 1 surface, and R is a vector which shows the direction of the reflected light in the position symmetrical with incident light with respect to a normal line direction. In other words, the direction L of the incident light and the direction R of the reflected light form the same angle Θ as the normal vector N.

The brightness of each pixel in the skin measured image corresponds to I in Equation (1). In addition, in Equation 1, other terms except for I and N may obtain values in advance. For example, the direction L of the incident light with respect to the surface of the skin 1 may be obtained by placing a reflector near the subject and photographing the reflector at the time of photographing the skin, and by looking at the light source reflected on the reflector.

On the other hand, as described above, a plurality of images of the skin are obtained by changing the position of the light source. By substituting the brightness (I) of each pixel in the plurality of images into the above Equation 1, the vector N representing the normal of the skin surface in the area covered by each pixel can be calculated. In the present specification, the first normal map refers to skin structure information obtained by calculating normal information on all pixels of an image photographing skin in the above manner.

6A and 6B are images that are displayed on the first normal map generated by the above-described process. The image of FIG. 6A is a result of rendering using Lambert i an shading to express the first normal map, and the values of the components of the x-, y-, and z-axis of the normal vector are respectively red ( The result obtained by rounding off to R), green (G) and blue (B) is shown. Meanwhile, the image of FIG. 6B shows a result of rendering using only shadows without applying color to the first normal map.

The microstructure calculation unit 52 generates a second normal map corresponding to the microstructures such as wrinkles and / or pores on the skin by using the first normal map generated by the normal calculation unit 51. can do. The first normal map generated by the normal calculation unit 51 is a normal of the skin surface. Corresponds to the information. However, since the subject's face is a three-dimensional curved surface, the normal information of the skin in the first normal map includes not only the microstructures such as wrinkles and / or pores, but also the overall outline of the subject's face. Thus, the first normal map alone is difficult to know information about the microstructures such as wrinkles and / or pores present in the skin of the subject.

In order to solve this problem, the fine structure calculator 52 may include a low-frequency map generator 521 and a second normal map generator 522. The low frequency map generator 521 may calculate a low frequency map that is subjected to contour information of the skin from the first normal map. The low frequency map may be calculated through a process of obtaining a low frequency component by applying a Gaussian filter to the first normal map and normalizing it again. In this case, the width of the Gaussian filter to be applied may be appropriately determined so that microstructures such as wrinkles and / or pores of the skin are not visible in the low frequency map.

FIG. 7 is an image displayed on a low frequency map calculated from a first normal map by a low frequency map generator. As shown, in the conventional skin image, fine structures such as wrinkles and pores are not observed in the low frequency map, and only the components that cover the entire contour of the face such as the nose and the lip protrude and the periphery of the eye are depressed You can see what is observed in.

Next, the second normal map generator 522 removes the second normal map corresponding to the microstructure of the skin by removing the low frequency map calculated by the low frequency map generator 521 from the original first normal map. Can be generated. The second normal map is a method of first calculating a rotation operation for converting a low-frequency map including contour information of the skin into a map on a plane, and then applying the calculated rotation operation to the original first normal map. Can be generated. As a result, the components corresponding to the entire contour of the skin in the normal vector corresponding to each pixel of the first normal map are removed by a rotation operation. Therefore, in the finally generated second normal map, only components that are applied to the microstructures such as wrinkles and / or pores existing on the skin except the overall outline of the skin remain.

In one embodiment, the microstructure calculation unit 52 may further include a scaling unit 53. The scaling unit 53 may perform scaling in one direction to further emphasize the microstructure in the second normal map generated by the second normal map generator 522. For example, assuming that the microstructure of the skin is represented by a curved surface of z = f (x, y), the normal vector N may be expressed as Equation 2 below. <54> [Equation 2]

_<55> N = (-df / dx, ᅳ df / dy, 1)

In this case, the fine structure may be emphasized by scaling the curved surface z = f (x, y) in the z-axis direction. For example, a curved surface scaled with a scale factor s may be z = sf (x, y), and as a result, the normal vector N may be expressed as Equation 3 below.

<57> [Equation 3]

<58> N 二 (-s df / dx, -s df / dy ^J , 1)

This means that microstructures can be strengthened and / or weakened by controlling the size of the xy component in the normal vector. In the above-described embodiment, the example of scaling the curved surface in the Z-axis direction has been described, but the scaling direction may be appropriately determined in the vertical and / or horizontal directions according to the direction of the component to be emphasized in the microstructure.

8A and 8B are images reflected on the second normal map generated by the microstructure calculating unit. FIG. 8A illustrates a second normal map generated from the first normal map, and FIG. 8B illustrates a result of performing scaling to emphasize components in the horizontal direction in the second normal map of FIG. 8A. As shown, it can be seen that in the crab 2 normal map, only fine structures such as wrinkles and pores are prominently displayed except the overall outline of the face.

The wrinkle component calculation unit 53 may generate a scalar mapol generated only by the wrinkle component of the skin from the second normal map generated by the microstructure calculation unit 52 and corresponding to the microstructure of the skin. In the present specification, the wrinkle component refers to only a structure having a predetermined size or more among the microstructure of the skin. For example, the wrinkle component may refer to a separation of only a relatively large coarse wrinkle portion except for a relatively small portion such as pores or fine lines in the second normal map. At this time, the size of the fine structure divided by the thick wrinkles may be appropriately defined according to the purpose of measuring the skin structure, etc., it is not limited to any one value.

In order to generate a scalar map that is subjected to the wrinkle component, the wrinkle component calculator 53 may include a vector map generator 531 and a scalar map generator 532. First, the vector map generator 531 may generate a two-dimensional vector map by extracting and normalizing only components of the normal vectors in the X- and y-axis directions of the second normal map.

Next, the scalar map generator 532 filters the two-dimensional vector map generated by the vector map generator 531 using an elliptical Gaussian filter. can be filtered. The output of the elliptical Gaussian filter is high if the direction of the vector matches the direction of the filter in the two-dimensional vector map. By using this, the output value is calculated while changing the direction of the elliptical Gaussian filter in each vector, and the resulting maximum output value can be used as a scalar value of the corresponding vector.

In one embodiment, the scalar map generation unit 532 determines the direction of the elliptical Gaussian filter.

It is possible to calculate a scalar value for each vector by rotating it 360 ^degrees . Alternatively, the scalar map generator 532 may extract only the wrinkle component corresponding to the angle by adjusting the rotation angle of the elliptical Gaussian filter to a preset angle. The skin of the subject differs in the direction of wrinkles according to each area. Therefore, instead of rotating the elliptical Gaussian filter in all directions, only the wrinkle component in the desired direction can be extracted by calculating a scalar value while rotating in a predetermined angle range including the wrinkle direction in the measurement area.

In addition, the rotation interval of the elliptical Gaussian filter in the scalar map generator 532 may be appropriately determined based on the purpose of skin structure measurement. For example, a scalar value corresponding to each vector may be calculated while rotating the elliptical Gaussian filter at 5 ^° intervals, or the rotation interval of the elliptical Gaussian filter may be determined by any other different value such as or or io °. have.

The scalar map can be generated by performing the above process on all the vectors of the 2D vector map. The scalar map generated as described above has a high scalar value in a region where a relatively large microstructure is located, such as a thick wrinkle. Therefore, using the scalar map, only the fine wrinkles can be observed except for pores and fine wrinkles in the skin microstructure. In one embodiment, the wrinkle component calculation unit 53 further includes a threshold applying unit 533 for extracting only pixels whose scalar values exceed a predetermined threshold in order to more clearly distinguish the wrinkle components in the scalar map. You may.

FIG. 9 is an image corresponding to a result of extracting only pixels having a value exceeding a specific threshold from a scalar map generated by the wrinkle component calculating unit. As shown, it can be seen that only relatively large coarse wrinkles are observed except for small pores and fine wrinkles.

In an embodiment, the analyzer 50 may further include an elasticity calculator 54 for calculating skin elasticity information using the first normal map. This can be done by computer simulation using the first normal map. For example, the angle of the first normal map You can place a virtual ball on a pixel and simulate the ball's movement according to the pixel's normal vector. As a result, the direction of movement of the ball can be determined according to the direction of the normal vector. In addition, the speed of the ball movement is relatively high at the position where the slope of the normal vector is large, whereas the speed of the movement of the ball appears at the position where the slope of the normal vector is small.

As described above, the motion of the ball may be simulated in each pixel of the first normal map, and the elasticity information of the skin may be calculated using the location of the ball over time. For example, by measuring the movement of the ball starting from each pixel of the first normal map at regular time intervals, and by connecting the measured position of the ball in each time step, the skin elasticity information similar to the contour line is obtained. It can also be calculated.

10 is a flowchart illustrating a method for measuring skin structure according to an embodiment. The skin structure measuring method may be performed using the skin structure measuring apparatus according to the above-described embodiment with reference to FIGS. 1 to 9.

Referring to FIG. 10, the skin image may be photographed in a state in which light is irradiated by each light source while sequentially irradiating light onto the skin by a plurality of light sources having different light irradiation directions (S1). Next, a first normal map including normal information of the skin surface may be generated using the plurality of photographed images (S2).

In an embodiment, the second normal map corresponding to the microstructures such as wrinkles and / or pores present in the skin may be generated using the first normal map. To this end, it is possible to first calculate a low frequency map that is subjected to contour information of the skin from the first normal map (S3). Next, by removing the calculated low frequency map from the original first normal map, a second normal map corresponding to the microstructure of the skin may be generated (S4). Except for the overall outline of the skin, only the components that are processed on the microstructures such as wrinkles and / or pores remain in the generated second normal map. In one embodiment, scaling may be performed in one direction to further emphasize the microstructure in the second normal map generated by the above-described processes (S3 and S4) (S5).

In one embodiment, a scalar blind generated only on the wrinkle component of the skin may be generated from the second normal map supported by the microstructure of the skin as described above. To this end, first, only components in the X- and y-axis directions of each normal vector are extracted from the second normal map and normalized to generate a 2D vector map (S6). Next, a scalar map may be generated by filtering the generated two-dimensional vector map using an elliptical Gaussian filter (S7). By using the scalar map to remove pores and fine wrinkles in the skin microstructure Only thick wrinkles can be observed. In an embodiment, in order to more clearly distinguish the wrinkle component from the scalar map, a process of extracting only pixels whose scalar values exceed a predetermined threshold may be further performed (S8).

Meanwhile, in one embodiment, the skin elasticity information may be calculated using the first normal map (S9). For example, by simulating the motion of a virtual ball at each pixel of the first normal map, measuring the ball's movement at regular intervals, and connecting the measured ball's position in each time step. Skin elasticity information can be calculated.

In the present specification, a method for measuring skin structure according to an embodiment has been described with reference to a flowchart shown in the drawings. For simplicity, the method is shown and described as a series of blocks, but the present invention is not limited to the order of the blocks, and some blocks may occur in different order or simultaneously with other blocks than those shown and described herein. In addition, various other branches, flow paths, and blocks may be implemented in order to achieve the same or similar results. Moreover, not all blocks shown for the implementation of the method described herein may be required.

Although the present invention has been described with reference to the embodiments shown in the drawings, this is merely exemplary and various modifications and embodiments may be made therefrom by those skilled in the art. Will understand. However, such modifications should be considered to be within the technical protection scope of the present invention. Therefore, the true technical protection scope of the present invention will be defined by the technical spirit of the appended claims.

Industrial Applicability

Embodiments relate to an apparatus and method for measuring skin structure.

Claims

[Range of request]

[Claim 1]

A plurality of light sources arranged in one direction different from each other with respect to the skin to be measured, and configured to irradiate light sequentially on the skin; and

And a photographing unit which photographs skin to generate a plurality of images respectively supported by the plurality of light sources.

[Claim 2]

The method of claim 1,

The light source comprises a flash device.

[Claim 3]

The method of claim 2,

The light source is a skin structure measuring apparatus, characterized in that it comprises a metal halide lamp.

[Claim 4]

The method of claim 1,

Skin structure measuring device further comprises a fixing portion configured to fix the position of the skin.

[Claim 5]

The method of claim 1,

The apparatus for measuring the skin structure further comprising a support unit configured to support the photographing unit and the plurality of light sources and to be movable relative to the skin.

[Claim 6]

The method of claim 1,

Skin structure measuring apparatus further comprises an analysis unit for calculating the structure information of the skin by using the plurality of images.

[Claim 7]

The method of claim 6,

The analyzer includes a normal calculation unit configured to generate a first normal item that is subjected to normal information of the skin by using brightnesses of the plurality of images.

[Claim 8]

The method of claim 7,

The analyzer further comprises a microstructure calculation unit configured to generate a second normal item that is subjected to microstructure information of the skin by using the first normal map.

[Claim 9]

The method of claim 8,

The microstructure calculation unit,

A low frequency map generator for generating a low frequency map that is applied to skin contour information by applying a Gaussian filter to the first normal map; And

And a second normal map generator for generating the second normal map by removing the low frequency map from the first normal map.

[Claim 10]

The method of claim 9,

The microstructure calculation unit further includes a scaling unit to scale the second normal map in one direction.

[Claim 11]

The method of claim 8,

And the analyzing unit further comprises a wrinkle component calculating unit configured to generate a scalar item corresponding to the wrinkle component information of the skin using the second normal map.

[Claim 12]

The method of claim 11,

The wrinkle component calculation unit,

A vector map generator for generating a two-dimensional vector map by extracting a horizontal component from the second normal map; And

And a scalar map generator for generating the scalar map by applying an elliptical Gaussian filter to the two-dimensional vector map.

[Claim 13]

The method of claim 12,

And the scalar map generator is configured to calculate an output value of the elliptical Gaussian filter while rotating the elliptic Gaussian filter at a predetermined angle.

[Claim 14]

The method of claim 12,

The wrinkle component calculating unit further includes a threshold applying unit extracting an area having a value greater than or equal to a preset threshold value in the scalar map.

[Claim 15]

The method of claim 7,

The analysis unit, the skin structure measuring apparatus further comprises a elasticity calculator for calculating the skin elasticity information using the first normal map.

[Claim 16]

Photographing a plurality of images projected to each of the plurality of light irradiation directions while sequentially irradiating light to the skin in a plurality of different light irradiation directions; And

And generating a first normal map corresponding to normal information on the surface of the skin by using brightnesses of the plurality of images.

[Claim 17]

The method of claim 16,

Generating a low frequency map based on skin contour information by applying a Gaussian filter to the first normal map; And

And removing the low frequency map from the first normal map to generate a second normal map that is adapted to the microstructure information of the skin.

[Claim 18]

The method of claim 17,

Generating the second normal map,

Calculating a rotation operation for converting the low frequency map into a map on a plane; And

And applying said rotation operation to said first normal map.

[Claim 19]

The method of claim 17,

And further comprising scaling the second normal map in one direction.

[Claim 20]

The method of claim 17,

Generating a two-dimensional vector map by extracting a horizontal component from the second normal map; And

And applying a elliptic Gaussian filter to the two-dimensional vector map to generate a scalar item that is supported by the wrinkle component information of the skin.

[Claim 21]

The method of claim 20, The generating of the scalar map may include calculating an output value of the elliptical Gaussian filter while rotating the elliptical Gaussian filter at a predetermined angle.

[Claim 22]

The method of claim 20,

And extracting an area having a scalar value greater than or equal to a preset threshold from the scalar map.

[Claim 23]

The method of claim 16,

The method of claim 1, further comprising calculating skin elasticity information from the first normal map.